Charge forming device



Feb. 21, 1939. F. T. IRGl-:Ns 2,148,071

CHARGE FORMING DEVICE Filed Feb. 1, 1936V 7.7 u 70 I Y' 4 INVENTO'R EMMf7/MJ A/TToRNEYs M "Figure 'I is a fragmentary detail view partiaJlyl'UNIT-ED STATES PATENT OFFICE 2,145,071 CHARGE romulNG nevica Finn T.Irgens, Wauwatosa, Wis., assignor, 'b mcsne assignments, to Outboard,Marine Manufacturing Company, Wilmington, Del., a corporation ofDelaware Application February 1,.,

This invention relates to improvements in charge forming devices. Thepresent application is a continuation in part containing subject matterdivisional with respect to my Patent 2,069,315,

5 for improvements in Internal combustion engines, granted February 2,1937.

It is `the primary vobject of the invention to lprovide novel andimproved charge forming means incorporated directly into the top orcover o of a fuel reservoir, thus eliminating a float. chamber andproviding simplified mechanism for mixing a hydrocarbon fuel with airand for controlling the formation and edelivery of the mixture.A l

.i More specifically, it is one of the principal purposes of theinvention to provide a novel and improved type of mixing valve employinga resilfr iently yieldable flat spring which is biased normally to closeboth4 the air and fuel passages 50 and which is opened to a greater orless degree by the diiferential pressures existing across the K'platevto admit fuel in proportion to the airA admitted..

It is`a 'further object of the invention to pro- 5 vide a novel andimproved form of choke for use in a device of the character describedand also to provide a novel and improved throttle valve arranged to beautomatically controlled in accordance with timer settings.

10 It is a further purpose of the invention to provide convenientlycontrolled means for regulating -the flow of fuel to the mixing nozzleand l for otherwise facilitating the incorporation of a charge formingdevice-directly in the top or cover 35 of a fuel reservoir. A

In the drawing:

Figure 1 isy a view partially in sectionA and partially in sideelevation showing the power head 'of an outboard motor equipped with a ocharge forming device embodying the present in vention. A l

Figure 2is a plan view of the fuel reservoir as it appears with thecover of the charge forming device removed. Y

Figure 3 Vis a detail view taken in section on the line 3 3 of Figure 2.l

Figure 4 is a fragmentary plan view of a portion ofthe timer and aportion of the throttle valve of the charge forming device.V

' Figure 5' is adetail view on an enlarged scale taken in section on theline 5--5 of Figure 3. l Figure 6 is a fragmentary detail view of the 1mixing valve arrangement slightly modified from the structure shown inFigure 1.

193s, serien Ne..s1`,911

in front elevation and partially in transverse section `through aportion ofthe fuel reservoir and the cover applied thereto. r

Like parts are designated by the same. reference characters throughoutthe several views.' 5 The power head as herein disclosed comprises anengine having a crank case .6, crank shaft 1, connecting rod 8, piston9, cylinder lli, flywheel' magneto, timer plate l2, and spark' plug I3,all of which may be of conventional design ex- 10 cept as hereinafterspeciiled. l

VThe front -side of the crank case 6 is formed to provide a seat towhich the top section '35 of the fuel reservoir 36 is secured. 'I'hescrews 3l shownin Fig. 2. support the lower section of the l5 fuelreservoir from the-upper section thereof.

The tiller by which the entire outboard motor is vdir'igibly controlledis mounted directly on the is made permanent, 'Ihe flexibility of thehandle 3o 'grip 32 per se takes up vall torquevibration.-

The upper and lower sections of the fuel reservoir are preferably bothmade of die castings and consequently are comparatively rigid. Also, byreason of this fact, they may readily be varied 35 in thickness asrequired to provide the various ducts and passages hereinafter to bedescribed.

A removable closure is provided een rer the 1ntroduction ofthe liquidfuel. Y `In the lower unit of the fuel reservoir there 40- is an annularflange Il (see'Fig. 3) threaded to receive a clean-out plug 42. Through'the opening `thus provided, a fuel supply pipe may be' introducedforconnection with a bossaVV formed on the underside of the top sectionof the 45 reservoir. 'I'he inlet at the lower end of pipe ispreferablytcovered by a screen `l5.v Within the screen 4511s a passage28 leading to a chamber 29 within which I preferably provide la checkvalve lli (Fig. 5), although such a check'valve 50A isunnecessary'fb'ecause of the function of thel spring valve hereinafter tbedescribed. l

' At its upper end the -fuel pipe I3 communi-` eatee with e duet 4s inthe interior er e plug n with which a needle valve 4l 'is in screwthreaded "55 connection. 'Ihe plug 41 provides a suitable seat for theneedle valve and also carries conventional packing for the v.stemthereof.

Beyond the needle valve the duet 46 has an upward extension 49 (Figs. 2and 3) terminating in a jet opening 5U at the upper face of the topsection 35 of the fuel reservoir.

The longitudinally extending boss 52 in the top section 35 of the fuelreservoir through which duct extension 49 leads to jet opening 50, hasan air admission port 53 leading to an interior air passage openingadjacent the jet so trirough a U-shaped port 55 in the substantiallyplaniform Upper surface 56 of the section 35 of the reservoir. Beyondthis point there is another duct 51 leading downwardly and communicatingwith a duct 58 which carries the mixture to the interior of the crankcase.

Applied to the flat surface 56 of the top member 55 of the fuelreservoir is a cap 59 channeled at 5l to provide a passage communicatingwith passages 51 and 55 which lead to the crank case, and alsopotentially communicating` with the jet port 50 and the passage 5 4through which the fuel and air are respectively supplied. It is inthepassage III that carburetion actually occurs.

Connned between'the cap 59 and the top sec- *I tion I5 of the fuelreservoir is a mixing valve comprising a ilat spring plate 55 whichcovers the U- shaped air port 55 and the fuel ,iet portlil. The end ofthe spring valve plate above the fuel port is fr ee and the other end isfixed. Thus the pressure 'diiferential between the crank case and theatmosphere during the compression stroke of the piston in its cylinderwill cause atmospheric air topass under the margins 51 of cap 59 andthrough port 53 and passage 54 to port 55, where the air pressure willcause valve 55 to bow upwardly, thus admitting air to the mixing passage5 5 and directing its now across the jet orince 5l.'

The greater the pressure diiferential, the greater will be the upwardmovement of the spring mixing valve. and the greater will be the vacuumon the fuel orifice, thereby producing increasedilowofbothairandgasolinetosupplytheincreased demand. rllhe mixing valve55 comprises a fairly light spring platev and serves as a check valve toprevent the escape of mixture when the mixture'is compressed in thecrank case.

' It has been found that the shape of port 55 and passage 51, as clearlyshown in Fig. 2, is admirably adapted to ensure a proper proportion offuel and air subject, of course, to the control of the fuel by means lofthe needle valve. The exact type of spring must be determined byexperiment since the requirements'will vary with each installation.'

-but its resilience is not critical and itis only desirable that itsrange of movement between closed and open positions in passage 55 shouldapproximately .correspond to the ranse -of airflow vthrough the passageso that the valve will'be fully .iopening almostto the marginofport55,assh.'xwnV open in rponseto maximum air requirements and airrequirements. i The jet opening I need not necessarily open midwaybetween the air port l5 and the mixture port 51. as shown in Figures1'and'2. I have found it desirable for many purposes to carry the Jet at54|, in Figure 6 (a modincation), Where this isdone, the check valve 3lis not ataILnecessary, since practically no back pressure i municatedtothe fuel.

is. ever comressmir ai@ designed as u have' s liras area inproportionate theamount of depth open in response to-minimum of fueltherein. Therefore the head against which the fuel must be drawn to thejet orifice 50 will not vary as greatly as would be the case if a highnarrow tank were used. The design is preferably such that `at normaloperating speeds there will be ample depression at the Jet orifice todraw the fuel from the bottom of the' tank (at maximum head).

. At the same time the depression available for lifting the fuel to thejet should not exceed the actual requirements of .the motor, sinceotherwise the motor will operate at low volumetric eilleiency.Accordingly 'I have provided means by which the volumetric eflloiencymay be at a maximum during nonnal operating speeds and means islprovided to increase the depression in the mixing passage at low enginespeeds suiliciently to compensate for the decrease of vacuum in thecrank case at such speeds'.

In this, as in many other two cycle engines, speed is controlled by thetimer, the plate I 2 being mounted for angular adjustment about the axisof the crank shaft'under control of the handle 85. Since the position ofhandle 68 and plate i! is directly related to engine speeds,.I am ableto provide on plate l2 a cam at 69 having a surface of the generallyhelical fon shown in Fig. 4. .This cam acts upon 'a cam follower 10which is in the form of a plunger and is effective to choke the airinlet port 53.

The choke compri a slide valve 12 removable across the top of port 53vtorestrict the opening thereof. -A yoke 13 carried by the slide valveengages a spoof-shaped nut 14 which is screw threaded to the camfollower plunger 10, the nut being restrained-by the yoke from rotation.A compression spring at 15 acts on nut 14 to maintain the slide valve 12in its normally retracted wide open position and to maintain the lcamfollower 1 I in abutment with theoperating surface of cam Il.

' As the lever Il is actuated toward theretarded spark position shown inFig. 4 it pushes the cam follower rod 1l to the right as viewed in Pis.1, until the' slide-valve 12 partially covers the apertin'e 58. Theexact degree of coverage may be controlled and adjusted by the rotationof the cam follower rod 1I in nut 14, and by the end of the ma beingexposed and provided with a screw It is also desirable to choke tire airintake forv I starting. ll'or this purpose a separate choke mayconveniently be provided comprising a piston-type slide valve in thebore beneath the inlet port 53 at 1l.- This choke valve is mounted on' avalve 11 having an exposed button at 14 normally held in the retractedposition by a compression spring at 1I. By pressing the button theoperator may substantially close loif the air below port 5l, as will beobvious from inspection of Pig. '1. f I claim:

l. The combination with a fuelreservoir from which carburetion iseifected directly without the.

intermediation vof a float valv'e. of a charge forming device incommunication with said reservoir to receive fuel therefrom. andprovided with an'.

air inlet. a valve vcontrolling air ilow into said device, a mixingvalve automatically regulating themixture of air with fuel from saidreservoir and subject to variation in rponse relative todifferentialpressures thereacross, engine speed lcontrol mechanismuponthe adjustment of which 'such din'ermtial pressures are dependent.

discharge duct leading from said seat, and fuel l and means connectedwith said mechanism for adjusting said iirst mentioned valve in adirectionv adapted for compensation for pressure iluctuations to whichsaid mixing valve is subject.

2. Ina device of the character described, a. charge forming devicehaving a fuel nozzle and an air inlet, valve controlling said inlet forvarying the suction at the nozzle, a spring -urging said valve towardits open position, and a cam provided with a follower connected withsaidvalve for movement thereof in lopposition to said about the point ofcommunication of said passages, and a spring plate having one endanchored t saidseat and the other end free for resilient movement yfromsaid seat for the simultaneous opening of said passages. f

4. A charge forming device comprising the combination with meansproviding a mixing chamber having a surface constituting a valve seat.and ducts for air and fuelv leading through said surface to saidchamber, of a spring plate having one end anchored and a resilientlyyield` able end biased toward a. position of engagement with said seatto close concurrently the communication of both ducts with said chamber,

said free end being yieldable'in response to differential pressures toopen said ducts. 5. In a device of the character described; the

combination with a fuel reservoir having a cover provided with a valveseat on its `upper face, a

and air admission ducts leading through said seat in proximity to eachother, of a. cap member extending `over said seat and providing a.mixing chamber within which said'seat is disposed and from which saiddischarge duct leads, and

a mixing valve comprising a spring plate having a yieldable end portionbiased toward engagewith a valve seaton its upper face, a

discharge duct leadingl from said seat, and fuelandairadmissiondtsleadingthroughsaid seatinproxlmitytoeachothenofacapmemberextending over said seat and providinga mixing chamber within whichsaid seat is disposed and from which saiddischarge duet leads, and a mixing valve comprising a springplatehavlnga yieldable end portion biased toward engagement with saidat to closessidfuel and air admission ducts and resiliently yieldablefrom saidVseatfol'thesunnita-nenasopeningofsaidducts,

7otiqmbstweentheexternalIihnmsrihlereandthe` said'coverbeingaperhnedtoaiford communicaair admission duct, together with valvemeans for the restriction of said aperture to regulate air admissiontoward said seat.

7. In a device of the character described, the combination with a fuelreceptacle having a cover provided with a boss, the boss being surfacedto Y provide a valve seat, of a fuel duct provided with needle valvecontrol and opening from said receptacle through said seat,l an air ductin communication with the atmosphere and extending through said boss andopening through said seat, means coacting with said seat to provide amixing chamber withinwhich said seat -is disposed,

' and a spring plate secured to said seat beyond said air duct from saidfuel duct and having its free end portion over said fuel duct and itsintermediate portion over said air duct, said plate being yieldable inresponse to pressure diilerentials to open said fuel and air ducts andto direct over said fuel duct a flow of air generally proportioned tovsuch pressure differential.

8. The combination with a charge forming device provided with an airpassage and a fuel duct communicating therewith and a. valve seat acrosssaid passage adjacent said duct, of a check valve biased for movementtoward said seat and yieldable therefromresponsive to the flow ofdiierent volumes of air through said passage, a choke valve spaced fromsaid seat in the path of: air

moving through said passage toward said duct, .and means for moving saidchoke valve progressively in a direction-to close said passage inaccordance with a decrease of flow of air therein, whereby therespective openings of said choke valve and said rstmentioned valve arecon,

currently reduced.

9. In a device of the character described, the combination with a chargeforming device provided with an air passage having a seat and a ductopening into said passage' adjacent said seat, ofa fuel reservoirwith-which said duct communicates for the carburetion of air traversingsaid passage, a valve biased for movement toward said seat and yieldabletherefrom in ,accordance with the now of air traversing said passage,means for varyingthe flow of air through" said passage independently oi'the movement of said valve, said valve being automatic in its operation,and a second valve comprising means for progressively choking saidpassage, Yin the path of air traversing saidpassag'e toward said seat'and duct, and means foractuating said second combinai'aion with a viiuidreceptacle and a supporting bracket comprising a cover thereforprovidedwithan air aseatanda duct opening into said passage fromsaidreceptacleadjacent said seat, of a. check valve comprising a springreed having a natural bias toward said seat and yieldable therefrom inac-` cordance with airflow through said passage and 'over said duct, anda second valve adjustable passage in the path of air traversing saidpassage toward said duct and seatrand meansforactuatingsaidvalve.

" FINN T. IBGENS.

